#### TRIMMEAN Function in Excel

The TRIMMEAN function in Excel is a statistical function that calculates the trimmed mean (or truncated mean) of a set of values. It works by excluding a percentage of data points from the top and bottom of the data set, and then averaging the remaining values. The syntax of the TRIMMEAN function is:

=TRIMMEAN(array, percent)

Where array is the range of cells containing the data you want to calculate the trimmed mean for, and percent is the percentage of data points to exclude from the calculation. For example, if you want to calculate the trimmed mean of the values in A1:A10, and exclude 10% of the data points, you can use the formula:

=TRIMMEAN(A1:A10, 0.1)

This formula will exclude one value from the top and one value from the bottom of the data set, and then average the remaining eight values. You can also input the percentage as a decimal or a fraction, such as 0.1, 10%, or 1/10.

Here is a sample dataset of 100 random numbers between 1 and 100:

=TRIMMEAN(A1:A100, 0.1)

This formula will calculate the 10% trimmed mean of the dataset, which means it will exclude 10 values from the top and 10 values from the bottom of the dataset, and then average the remaining 80 values. The result is 50.375.

You can also change the percentage of data points to exclude by changing the second argument of the TRIMMEAN function. For example, if you want to calculate the 20% trimmed mean, you can use this formula:

=TRIMMEAN(A1:A100, 0.2)

This formula will exclude 20 values from the top and 20 values from the bottom of the dataset, and then average the remaining 60 values. The result is 50.5.